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Abstract Introduction: Castleman disease (CD) is a heterogeneous group of lymphoproliferative disorders classified anatomically as unicentric (UCD), oligocentric (OligoCD), or multicentric (MCD). Human herpesvirus 8 (HHV-8)-negative MCD is referred to as idiopathic MCD (iMCD), which includes clinical subtypes with distinct phenotypes and treatment responses: TAFRO (thrombocytopenia, anasarca, fever, renal dysfunction and/or reticulin fibrosis, and organomegaly), idiopathic plasmacytic lymphadenopathy (IPL), and not otherwise specified (NOS). While UCD and iMCD, including TAFRO, have been more clearly defined, OligoCD and iMCD-IPL remain under-characterized, particularly in Western cohorts. This study aimed to validate the updated clinical classification of CD using a large institutional cohort by retrospectively reclassifying patients based on lymph node distribution and clinicopathologic criteria. We further examined whether OligoCD and IPL represent clinically and prognostically distinct entities compared to UCD or iMCD, and other iMCD subtypes. Methods: This study included 217 patients evaluated for CD at our institution between January 2004 and August 2024. All cases were reclassified based on the extent of lymph node involvement and iMCD subtype. UCD was defined as the involvement of a single lymph node region. OligoCD was defined as involvement of ≥2 contiguous lymph node stations without sufficient systemic symptoms to meet iMCD criteria. Patients with POEMS syndrome or HIV/HHV-8–associated CD, or lacking pathologic confirmation, were excluded. We evaluated clinical presentation, laboratory data, histopathology, treatment regimens, and outcomes. The primary endpoint was overall survival (OS), and the secondary endpoint was event-free survival (EFS), defined as time from first-line treatment to progression, change in therapy, or death. Survival outcomes were assessed using the log-rank test. Results: Among 217 CD patients, 123 (57%) had UCD, 43 (20%) had OligoCD, and 51 (23%) had iMCD. iMCD-defining symptoms were more common in iMCD compared to UCD and OligoCD. Among all, only fatigue and organomegaly were more common in OligoCD than in UCD. Laboratory values related to CD disease activities, including hemoglobin, serum creatinine, albumin, CRP, and plasma IL-6, showed significant differences in iMCD compared to UCD and OligoCD. No significant difference in the laboratory findings was observed between UCD and OligoCD, although patients with OligoCD had intermediate values between UCD and iMCD. With median follow-up of 4.0, 7.6, and 4.6 years for UCD, OligoCD, and iMCD, respectively, the 5-year OS was 99.0%, 97.7%, and 89.5% without differences among groups. Corresponding 2-year EFS rates were 95.2% for UCD, 68.0% for OligoCD, and 53.8% for iMCD. With OligoCD being the reference, UCD had a significantly lower hazard ratio (HR) of 0.20 (95% CI 0.10–0.41), and iMCD had a significantly higher HR of 2.0 (95% CI 1.1–3.6). Among OligoCD patients initially treated with surgery (40%), none required systemic therapy thereafter. Those treated with rituximab or glucocorticoid monotherapy required subsequent therapy in 50% and 43%, respectively. Within iMCD subtypes (TAFRO (n=16), IPL (n=9), and NOS (n=26)), the 5-year OS was 80.4%, 100%, and 91.0%, respectively, without significant differences among the subtypes. However, 1-year EFS rates were 40.2%, 100%, and 65.6%, respectively, with an HR of 4.3 (95% CI 1.2–15.2; p = 0.02) in TAFRO and 1.6 (95% CI 0.77–3.5) in NOS compared to IPL. Patients with IPL had a high rate of symptomatic improvement assessed by a physician of 89% with a longer time-to-next treatment. Conclusions: This extensive, retrospective cohort study supports the clinical relevance of updated CD subtype classification. As the present study spans two decades, it reflects evolving diagnostic criteria and therapeutic standards, including the 2014 FDA approval of siltuximab, the iMCD consensus criteria in 2017, with the addition of OligoCD and iIPL. The findings confirm the aggressive clinical nature of iMCD and suggest that OligoCD demonstrated intermediate features between UCD and iMCD, though closer to UCD in outcome. Also, the results reconfirmed that TAFRO is associated with severe symptomatic diseases, and validated that patients with IPL, even in the Western cohort, likely have favorable responses to treatment. Continued prospective efforts are warranted to confirm the clinical distinctions.

Abstract Introduction: Idiopathic multicentric Castleman disease (iMCD) is a rare lymphoproliferative disorder characterized by systemic inflammation of unknown etiology. Clinically, iMCD is classified into idiopathic plasmacytic lymphadenopathy (IPL), thrombocytopenia, anasarca, fever, renal dysfunction/reticulin fibrosis, and organomegaly (TAFRO), and not otherwise specified (NOS) subtypes. Among these, TAFRO and a subset of NOS cases share overlapping clinicopathological features and often follow a fatal clinical course. However, the pathogenesis remains largely undefined. This study combines a comprehensive transcriptomic analysis with histological assessment, focusing on vascular proliferation to elucidate the molecular mechanisms of the TAFRO subtype. Methods: We conducted a pathological analysis of nine IPL, nine TAFRO, and eight NOS cases, and performed transcriptome analysis from frozen lymph node specimens from 12, two, and four IPL, TAFRO, and NOS cases, respectively. Differentially expressed genes (DEGs) and KEGG pathway analysis were performed to identify significant pathways in TAFRO and NOS, with IPL cases as controls. Results: Histologically, TAFRO and NOS exhibited a significantly higher degree of vascularization than IPL (IPL vs TAFRO: p < 0.001, IPL vs NOS: p = 0.002). In addition, “whirlpool vessels” in GCs were seen in most cases in TAFRO and NOS (TAFRO: 9/9, 100%, NOS: 6/8, 75%), but not in IPL (IPL vs TAFRO: p < 0.001, IPL vs NOS: p = 0.007). Immunostaining for Ets-related gene revealed that the number of endothelial cells of TAFRO and NOS was significantly larger than that in IPL (TAFRO vs IPL: p < 0.001, NOS vs IPL: p = 0.002). KEGG pathway analysis revealed the PI3K–Akt signaling pathway was significantly enriched in the TAFRO/NOS groups. Immunohistochemistry of phosphorylated Akt and phosphorylated p38, both upstream and downstream effectors of the PI3K–Akt signaling pathway, were positive in vascular endothelial cells of TAFRO and NOS. Discussion: TAFRO and NOS exhibit marked angiogenesis and are histologically distinct from IPL. Furthermore, this angiogenesis is thought to be driven by upregulation of the PI3K–Akt signaling pathway, which may also contribute to extravascular fluid leakage, potentially leading to pleural and ascitic effusion or systemic edema observed in the TAFRO subtype. Conclusion: The present results suggest the crucial role of PI3K–Akt signaling pathway in TAFRO pathogenesis from transcriptomic and histopathological findings. This mechanistic insight may help elucidate the distinct pathogenesis of iMCD subtypes.

Abstract Introduction: The epidemiology and clinical characteristics of familial myelodysplastic syndromes/acute myeloid leukemia (MDS/AML) remain poorly understood, particularly among Native Hawaiians and Other Pacific Islanders (NHOPI). Methods: To investigate the real-world evidence in this area, we conducted a retrospective study at the Queen's Medical Center (QMC), Hawaii's largest tertiary referral hospital. The data was gathered from QMC's electronic medical record. Familial MDS or familial AML patients in this study were defined as MDS or AML occurring in a patient with a family history of MDS and/or AML. Patients with acute promyelocytic leukemia (APL), as well as those with a family history of APL, were excluded given the differences in disease characteristics and its genetic phenotype from other AML subtypes. Unspecified leukemia was defined when a patient had a family history of leukemia but the specific subtype was unavailable. Some patients underwent comprehensive panel testing, while others had targeted next-generation sequencing (NGS) assays ordered at the discretion of their treating physicians. NGS was performed at Clinical Laboratory Improvement Amendments (CLIA)-certified commercial laboratories. NGS panels typically included the following genes: ASXL1, BCOR, BRAF, CEBPA, CSF3R, DNMT3A, ETV6, EZH2, FLT3, HRAS, IDH1, IDH2, JAK2, KIT, KRAS, MLL, NPM1, NRAS, PDGFRA, PHF6, PML, PTPN11, RUNX1, SETBP1, STAG2, TET2, TP53, and WT1. Results: Among 1,686 MDS/AML patients presented between January 2012 and July 2023, 12 (0.71 %) had familial MDS/AML and 25 (1.48%) had a family history of unspecified leukemia. While no NHOPI were identified among familial MDS/AML cases, 20% of patients with a family history of unspecified leukemia were NHOPI. The median age at diagnosis of familial MDS/AML was 70 years, and 50% of familial MDS patients had MDS with low blasts based on the World Health Organization 2022 classification. Based on International Consensus Classification 2022 criteria, 25% had MDS, not otherwise specified (NOS) with multilineage dysplasia, and 25% had MDS, NOS with single lineage dysplasia. Among the eight patients with familial MDS, the median overall survival (OS) was 12.7 years, with an estimated 5-year OS rate of 75.0% (95% CI: 12.8–96.1), based on Kaplan–Meier analysis. In contrast, the three patients with familial AML had a median survival of 10.2 months and a 3-year OS estimate of 33.3% (95% CI: 0.90–77.4). For patients with a family history of unspecified leukemia, the median survival was not reached during the follow-up period. The estimated 5-year OS rate was 53.3% (95% CI: 12.5–82.7) for the 10 familial MDS cases and 53.3% (95% CI: 20.9–77.3) for the 13 familial AML cases. When combining all familial cases, the median OS for familial MDS (n = 18) was 12.7 years with a 5-year OS rate of 61.9% (95% CI: 26.8–84.0). The median OS for familial AML (n = 16) was 0.90 years, and the estimated 5-year OS rate was 48.2% (95% CI: 20.8–71.3). When all cases were combined, there was no statistically significant difference in overall survival between patients with familial AML (n = 16) and those with familial MDS (n = 18), based on the log-rank test (p = 0.22). Regarding NGS, ASXL1 mutations were the most frequent in the cohort, detected in six of the 32 NGS tests performed (18.8%). Among patients with familial MDS, recurrent somatic mutations were observed in several genes. ASXL1 mutations were identified in two patients; one had a brother with MDS, and the other had a maternal uncle with unspecified leukemia. DNMT3A mutations were also found in two patients with familial MDS; one had a brother with MDS, and the other had a paternal uncle with MDS. SRSF2 mutations were detected in two patients; one had a brother with MDS, and the other had a granddaughter with leukemia. Additionally, SF3B1 mutations were found in two patients; one had a mother with MDS, and the other had a paternal uncle with MDS. Two patients with familial AML were found to have ASXL1 mutation, both with fathers who had unspecified leukemia. Otherwise, no other repeated mutations were found. None of the cases involved NHOPI patients. Conclusion: Our study offers new insights into familial MDS/AML within Hawaii's multiethnic population. Although no NHOPI patients were identified among the familial cases, our findings underscore the genetic heterogeneity and clinical variability of these disorders.

Abstract Background: Immune checkpoint inhibitors (ICIs) have been established as standard of care for patients with classical Hodgkin lymphoma (cHL), including relapsed or refractory (r/r) disease. However, ICIs discontinued in some patients due to treatment-related toxicities or disease progression may later be re-initiated. The outcomes of this common clinical practice of ICI re-initiation, or ‘rechallenge,‘ have not been evaluated. Here, we present real-world efficacy and safety data of ICI rechallenge in patients with cHL. Methods: We conducted a retrospective cohort study of patients with cHL treated with ICIs between 2015 and 2024 at Mayo Clinic sites. Patients were identified via institutional records using diagnostic and treatment codes. Included patients were adults ≥18 years with histologically confirmed diagnosis of cHL receiving ≥1 cycle of ICI therapy. Patients in the rechallenge cohort received a second course of ICI therapy following discontinuation of the initial ICI for any reason. The control cohort included patients with ICI discontinuation without subsequent rechallenge. Primary outcomes included progression-free survival (PFS), event-free survival (EFS), and duration of response (DOR), defined respectively as time from first ICI initiation to disease progression, time from first ICI initiation to disease progression, adverse events, treatment change, or death, and time from first recorded response per positron emission tomography–computed tomography until the occurrence of disease progression. Secondary outcomes included overall survival (OS), and incidence and severity of irAEs following ICI rechallenge. Survival outcomes were compared using propensity-score-matched (PSM) cohorts with a proportional Cox model. Results: A total of 145 patients were included. Of these, 30 (21%) underwent ICI rechallenge, while 115 (79%) received no subsequent ICI treatments. The median age was 40 years (interquartile range [IQR] 26-66). Most were male (59%), predominantly nodular sclerosis subtype (71%), Ann Arbor stage III-IV disease (65%), and ECOG ≤ 1 (96%). ICIs were utilized for r/r disease in 66%, with median 6 (IQR 4-13) cycles and follow up of 40.8 months (IQR 21.1–78.1). Patients received median 1 prior line of therapy (IQR 0-2.5). During initial ICI treatment, 34/145 patients (23%) experienced irAEs, including 17 patients (57%) in the rechallenge group and 17 (15%) in the non-rechallenge group. Most irAEs were of grade 1–2 severity, though 10 (30%) experienced grades ≥3 irAEs. irAE severity did not differ between groups. Among patients who underwent ICI rechallenge, the majority (53%) discontinued due to irAEs. The decision to pursue ICI rechallenge was driven predominantly by disease progression (63%). Among the 1:1 PSM cohorts using bone marrow transplant status and the International Prognostic Score, PFS did not significantly differ between rechallenged vs. non-rechallenged groups (HR 1.7, 95% CI 0.60–4.5, p=0.32). Similarly, no difference was noted among the groups in EFS and DOR using 1:3 PSM cohorts using the number of ICI cycles (HR 1.6, 95% CI 0.83–3.0, p = 0.16 and HR 1.6, 95% CI 0.37–7.0, p = 0.53, respectively). In the 1:1 matched cohort, ICI rechallenge was not associated with inferior OS compared to those without rechallenge (HR 1.6, 95% CI 0.48–5.4, p=0.43). irAE occurred in 20%, including pneumonitis (n=2), hepatitis (n=1), and pancreatitis (n = 1). Of the patients who had experienced irAEs during their initial ICI course, only two developed recurrent irAEs of the same type upon rechallenge, both at reduced severity. Overall, 80% of rechallenged patients did not experience any irAE with their second ICI course. Conclusions: ICI rechallenge was not associated with inferior PFS, EFS, DOR or OS compared patients without rechallenge. Among patients receiving ICI rechallenge after irAE, recurrence of same irAE was rare. ICI rechallenge may be a feasible and potentially effective strategy in selected patients with cHL.

BACKGROUND: Although obesity and insulin resistance (IR) are established risk factors for left heart dysfunction, their clinical impact in group 1 pulmonary hypertension (PH) remains unclear. We sought to determine the impact of excess adiposity versus IR on biventricular hemodynamic and functional reserve in group 1 PH. METHODS: Homeostasis model of insulin resistance and adiposity indices (body mass index [BMI], fat mass, waist circumference) were measured among group 1 patients with PH recruited to PVDOMICS (Redefining Pulmonary Hypertension Through Pulmonary Vascular Disease Phenomics). Functional capacity, and dynamic pulmonary capillary wedge pressure (PCWP) and right atrial pressure responses were compared stratified by obesity (BMI≥30 kg/m 2 ) and IR status (HOMA-IR≥2.6) using repeated-measure mixed models. RESULTS: Among patients with group 1 PH (n=418), 158 (38%) had BMI≥30 kg/m 2 (94 [60%] of whom had IR), and 260 (62%) had BMI<30 kg/m 2 (74 [28%] of whom had IR). Among those with waist circumference measurement (n=375), 287 (77%) had excess adiposity by elevated waist/height ratio, with 214 (57%) having elevated waist circumference. Patients with obesity had worse quality of life, exercise capacity and left heart remodeling, along with higher resting/dynamic PCWP, right atrial pressure and cardiac output ( P <0.0001 for all). Higher PCWP response with obesity persisted after adjusting for IR (IR-adjusted PCWP+2.5 mm Hg [95% CI, +1.4 to +3.6]; P <0.0001). All adiposity indices were consistently associated with PCWP response, but IR was not. Similar associations were observed between adiposity indices with higher right atrial pressure and cardiac output. Greater visceral adiposity as measured by body shape index (hazard ratio, 2.01 [95% CI, 1.16–3.47]; P =0.01) or weight-adjusted waist index (hazard ratio, 1.64 [95% CI, 1.10–2.46]; P =0.01) was associated with worse survival. CONCLUSIONS: Excess adiposity is common in group 1 PH, occurring in 4 out of 5 patients by the more sensitive waist/height ratio, in contrast to only 2 out of 5 patients having obesity by traditional BMI criteria. Excess adiposity is associated with higher biventricular filling pressures, cardiac output demand, worse functional status and reduced survival. These data support trials of adipose-reducing therapies in patients with group 1 PH and excess adiposity.

Achieving optimal unloading in patients with left ventricular assist devices (LVADs) is associated with improved outcomes but remains unattainable in some cases. We retrospectively reviewed 33 patients with a HeartMate 3 LVAD who underwent speed optimization with concomitant echocardiography and right heart catheterization for inadequate left ventricular (LV) unloading between January 2016 and December 2023. Patients were stratified based on left ventricular transmural pressure (LVTMP) into two groups: LVTMP ⩽7 mmHg and LVTMP >7 mmHg using a median split approach. Pulmonary capillary wedge pressure (PCWP) decreased in both groups with increased LVAD speed; however, the mean PCWP change per 100 rpm was significantly smaller in patients with LVTMP ⩽7 mmHg (−0.50 vs −0.99 mmHg per 100 rpm, p = 0.003). Comparative analysis demonstrated LVTMP’s superiority over established RV markers, with the strongest interaction effect for predicting speed optimization response. Changes in cardiac output were similar between the two groups. In univariate analysis, multiple hemodynamic parameters were significantly associated with reduced LVTMP, including right atrial pressure (OR = 1.27, p = 0.036), TPG (OR = 1.25, p = 0.037), DPG (OR = 1.69, p = 0.012), and PAPi (OR = 0.35, p = 0.019).LVTMP, as a surrogate for true LV preload, particularly in the context of RV failure, may offer predictive value for the success or failure of LV unloading with LVAD speed optimization.

Abstract Background and Aims Decrease in pulmonary vascular resistance (PVR) during exercise confers favourable prognosis in biventricular physiology, but its role in Fontan circulation remains unknown. This study aimed to evaluate the prognostic value of PVR index (PVRI) response to exercise in adults post-Fontan palliation. Methods Retrospective cohort of 88 adults (age ≥18 years) post-Fontan undergoing exercise (supine cycling) cardiac catheterization. Patients were categorized into absence (n = 23) or presence (n = 65) of exercise-induced reduction in PVRI. The clinical endpoint was a composite of death or transplantation. Results Age at catheterization was 32.2 ± 8.8 years, and 45.5% were female. Resting and exercise PVRI were 1.9 ± 0.9 and 1.2 (interquartile range [IQR] 0.8–2.1) WU·m2, respectively. Clinical, biochemical and echocardiographic parameters were not associated with PVRI response to exercise. During a follow-up of 2.2 ± 1.4 (IQR 1.2–2.6) years, resting PVRI was not associated with the clinical endpoint (hazard ratio [HR] 0.95 per WU·m2, 95% confidence interval [CI] 0.52–1.74; P = 0.86), whereas exercise PVRI was (HR 2.15 per WU·m2, 95% CI 1.24–3.73; P = .007). Exercise PVRI remained predictive of outcomes after adjusting for exercise pulmonary artery wedge pressure (HR 2.08 per WU·m2, 95% CI 1.19–3.62; P = .01) or clinical risk factors individually. Two-year event-free survival was lower in the no PVRI reduction than in the reduction group (67% vs 95%; P &lt; .001). Conclusions In adults post-Fontan, PVRI response to exercise is a robust predictor of clinical outcomes and offers additive prognostic information beyond resting invasive haemodynamic data and clinical risk factors, underscoring the importance of invasive exercise testing in this population.

Background Exercise cardiac catheterization is the gold standard for diagnosing diastolic dysfunction and impaired pulmonary reserve in patients with Fontan circulation. The diagnostic value of noninvasive parameters is unclear. Methods Patients who underwent simultaneous exercise hemodynamic evaluation and peripheral venous pressure (PVP) measurement were included. Echocardiographic surrogates for ventricular filling pressure were compared with invasive measures. Diastolic dysfunction was defined invasively as either resting pulmonary artery wedge pressure ≥12 mm Hg or exercise pulmonary artery wedge pressure >20 mm Hg. Results Twenty‐nine patients were included. Age at catheterization was 34±9 years. Atrioventricular valve systole‐to‐diastole duration ratio (S/D) and resting PVP were significant predictors of resting pulmonary artery wedge pressure (S/D: β=0.71 per 0.1 S/D [95% CI, 0.16–1.25]; P =0.01; PVP: β=0.68 per mm Hg [95% CI, 0.41–0.96]; P <0.001). By contrast, resting PVP was a predictor of diastolic dysfunction, whereas S/D was not. Based on these data, we proposed a 2‐tier assessment algorithm with the first tier considering resting PVP ≤15 mm Hg and S/D ≤1.1 and the second tier considering exercise PVP ≤25 mm Hg in those with 1 elevated resting parameter. This algorithm showed a positive predictive value of 88% (95% CI, 47%–100%), a negative predictive value of 90% (95% CI, 70%–99%), a sensitivity of 78% (95% CI, 40%–97%), and a specificity of 95% (95% CI, 75%–100%). Exercise PVP indexed to peak oxygen consumption also predicted invasively measured exercise pulmonary vascular resistance index (β=0.36 WU·m 2 per mm Hg/100 mL per min [95% CI, 0.08–0.64]; P =0.01). Conclusions This study presents a simple, noninvasive approach for evaluating diastolic function and pulmonary vascular reserve in patients with a Fontan circulation.

Introduction Semaglutide, a glucagon-like peptide-1 receptor agonist (GLP-1RA) used to treat type 2 diabetes mellitus (T2D), has potential associations with higher rates of diabetic retinopathy (DR) complications including proliferative DR (PDR) and diabetic macular edema (DME). The purpose of this study was to determine whether an association exists between semaglutide and PDR and treatment-requiring DR/DME. Research design and methods This was a retrospective cohort study of 14 databases (six administrative claims and eight electronic health records) in the Observational Health Data Sciences and Informatics Evidence Network. Adults with T2D on semaglutide, other GLP-1RA (dulaglutide, exenatide), or non-GLP-1RA medications (empagliflozin, sitagliptin, glipizide) from 1 December 2017 to 31 December 2023 were included. The association between semaglutide and PDR or treatment-requiring DR/DME was assessed using an active-comparator cohort design comparing new users of semaglutide as second-line T2D treatment to those on other GLP-1RAs and non-GLP-1RAs. Propensity score-adjusted Cox proportional hazards models were used to estimate hazard ratios (HRs). Network-wide HR estimates were generated using a random-effects meta-analysis. Results The study included 810 390 new semaglutide users for T2D. PDR risk for semaglutide was similar to dulaglutide (HR 0.81, 95% CI 0.42 to 1.54, p=0.51), empagliflozin (HR 0.83, 95% CI 0.53 to 1.30, p=0.41) and sitagliptin (HR 0.83, 95% CI 0.45 to 1.55, p=0.57) but was lower than glipizide (HR 0.59, 95% CI 0.39 to 0.88, p=0.01). The risk for treatment-requiring DR/DME for semaglutide was similar to empagliflozin (HR 0.66, 95% CI 0.43 to 1.02, p=0.06) but lower than dulaglutide (HR 0.53, 95% CI 0.31 to 0.91, p=0.02), sitagliptin (HR 0.46, 95% CI 0.26 to 0.81, p=0.008) and glipizide (HR 0.55, 95% CI 0.33 to 0.91, p=0.02). Conclusions and relevance We did not identify increased risk for either PDR or treatment-requiring DR/DME comparing semaglutide with other GLP-1RAs or non-GLP-1RAs. Patients with T2D should still undergo close eye care follow-up, particularly when initiating new antihyperglycemic medications.

Background: Group 1 pulmonary artery hypertension (PAH) is treated with three main drug classes: prostacyclin analogs (PCAs), endothelin receptor antagonists, and nitric oxide pathway drugs. PCAs may be administered via parenteral (intravenous (IV), subcutaneous (SQ)) or oral/inhaled routes. The role of parenteral versus non-parenteral PCAs in contemporary PH practice remains unclear. Objectives: To compare contemporary hemodynamic and survival outcomes between parenteral and non-parenteral PCA use. Methods: This retrospective study included patients with WHO Group 1 PAH, who underwent a right heart catheterization (RHC) at Mayo Clinic. Diagnosis required mPAP was ≥25 mm Hg, documented chart diagnosis and initiation of PAH therapy. Echocardiographic and repeat RHC parameters were collected and only patients started on PCA therapy were included. Patients were grouped based on intiiated PCA route: parenteral (IV/SQ) vs non-parenteral routes (oral/inhaled). Hemodynamic changes (post-pretreatment) were compared using t-tests and ANOVA for parenteral vs non-parenteral PCA. Survival was assessed using Kaplan-Meier curves, and Cox proportional hazards models. Results: Of 144 patients initiated on PCA after the first RHC, 89 (62%) received parenteral and 55 (38%) non-parenteral PCA.. At baseline, patients who started on parenteral PCA had more severe disease with higher mean PAP, RAP and PVR. On follow-up, parenteral PCAs led to greater reductions in mean PAP and RAP, with no differences in PVR, TPR, or CO changes. Survival was worse with parenteral PCA use even after adjusting for comorbidities and baseline hemodynamics (HR 1.93; 95% CI 1.17-3.18; p=0.009). Discussion: Parenteral PCAs were more often used in patients with more severe pulmonary vascular disease. Despite greater hemodynamic improvements, parenteral PCAs were associated with worse survival, likely due to more severe disease at baseline. Further research is needed to understand the role of PCA route in guiding treatment strategies.